Minimally invasive surgical (MIS) instruments are often preferred over traditional open surgical devices due to reduced post-operative recovery time and minimal scarring. Endoscopic surgery is one type of MIS procedure in which an elongate flexible shaft is introduced into the body of a patient through a natural orifice. Laparoscopic surgery is another type of MIS procedure in which one or more small incisions are formed in the abdomen of a patient and a trocar is inserted through the incision to form a pathway that provides access to the abdominal cavity. Through the trocar, a variety of instruments and surgical tools can be introduced into the abdominal cavity. The trocar also helps facilitate insufflation to elevate the abdominal wall above the organs. The instruments and tools introduced into the abdominal cavity via the trocar can be used to engage and/or treat tissue in a number of ways to achieve a diagnostic or therapeutic effect.
Various robotic systems have recently been developed to assist in MIS procedures. Robotic systems can allow for more intuitive hand movements by maintaining natural eye-hand axis. Robotic systems can also allow for more degrees of freedom in movement by including a “wrist” joint that creates a more natural hand-like articulation. The instrument's end effector can be articulated (moved) using a cable driven motion system having one or more drive cables that extend through the wrist joint.
A user (e.g., a surgeon) is able to remotely operate an instrument's end effector by grasping and manipulating in space one or more controllers that communicate with a tool driver coupled to the surgical instrument. User inputs are processed by a computer system incorporated into the robotic surgical system and the tool driver responds by actuating the cable driven motion system and, more particularly, the drive cables. Moving the drive cables articulates the end effector to desired positions and configurations.
Various types of end effectors, such as tissue graspers, forceps, needle drivers, and scissors, etc., have opposing jaws designed to open and close for a variety of reasons. In cable driven motion systems, the jaws of such end effectors open and close based on drive cable actuation (movement). In some applications, such end effectors can also incorporate electrocauterizing capabilities to simultaneously cauterize cut tissue.
Since robotic surgical systems operate based on electricity, it may be beneficial to incorporate a failsafe device that can be manually triggered without electrical input. This may prove advantageous, for example, in the event of an electrical disruption that renders the robotic surgical system inoperable. In such a scenario, a failsafe device might allow a user to manually articulate an end effector to safely release and remove the end effector from patient proximity.